The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
MIP is a solution for transmitting information for a mobile node. MIP is independent of communication media adopted by the mobile node. The MIP allows the mobile node to change its location, on condition that neither is the communication broken, nor is an application program restarted. At the same time, MIP provides an IP route mechanism, which enables the mobile node to connect to any link via a permanent IP address. In accordance with MIP, when a mobile node switches from a home link to a foreign link and receives an agent broadcast message sent from a Foreign Agent (FA), the mobile node obtains Care-of Address (CoA) from the agent broadcast message. The mobile node initiates MIP registration to its Home Agent (HA) to notify the HA of the CoA. Likewise, when the mobile node switches from the foreign link to the home link or breaks the connection with the network abnormally, a MIP deregistration is initiated to notify the HA of deleting the CoA.
A Centralized Worldwide Interoperability for Microwave Ranging (WIMAX) system provides two different modes for implementing MIP, i.e. Client MIP (CMIP) mode and Proxy MIP (PMIP) mode. The CMIP mode is identical to the conventional MIP mode, i.e. all functions of the mobile node are implemented on a mobile terminal, and the MIP registration or deregistration is initiated by a MIP client set on the mobile terminal. In this mode, the MIP registration or deregistration is opaque for the mobile terminal. In the PMIP mode, the MIP client is detached from the mobile terminal and set in a logical network element, such as a Proxy Mobile Node, in Accessing Service Network (ASN). In this mode, the MIP registration or deregistration is initiated by the proxy mobile node in the ASN, the foreign link locates at the ASN. Therefore, the MIP registration or deregistration is transparent for the mobile terminal. For the mobile terminal, it always works on the home link. A proxy mobile node may initiate the MIP registration or deregistration instead of a plurality of mobile terminals.
In the CMIP mode or the PMIP mode, a credential is established for each mobile terminal between the MIP client and the HA to implement the MIP registration or deregistration. The credential is saved in the HA of a mobile terminal and in an anchor proxy mobile node. The anchor proxy mobile node is a proxy mobile node specially used for saving the credential of the mobile terminal. The anchor proxy mobile node and a proxy mobile node corresponding to the home Base Station (BS) of the mobile terminal are configured in the same entity or different entities. The MIP registration or deregistration of the mobile terminal is initiated by the proxy mobile node corresponding to the home BS of the mobile terminal or the anchor proxy mobile node. If the proxy mobile node corresponding to the home BS of the mobile terminal and the anchor proxy mobile node is not configured in the same entity, the proxy mobile node corresponding to the home BS of the mobile terminal obtains the credential of the mobile terminal from the anchor proxy mobile node, and then initiates the MIP registration or deregistration of the mobile terminal.
The procedure of MIP registration or deregistration is described as follows. A MIP client calculates a Message Authentication Code (MAC) of a registration or deregistration request message according to an obtained or saved credential of the mobile terminal. The MIP client resides in a proxy node or an anchor proxy mobile node corresponding to the home BS of the mobile terminal. Then, the MIP client carries the MAC and an identity of a mobile terminal (MT ID), in the registration or deregistration request message and sends the request message to the HA. The HA first searches for and acquires the credential of the mobile terminal upon the receipt of the registration or deregistration request message. Then, the HA calculates the MAC of the registration or deregistration request message according to the credential. Then, the HA matches the calculated MAC with the MAC carried in the registration or deregistration request message. If the calculated MAC is matched with the MAC carried in the registration or deregistration request message, the HA sends a registration or deregistration response message to the MIP client. The registration or deregistration response message carries the MT ID and the MAC of the registration or deregistration response message, the MAC is obtained according to the credential of the mobile terminal. Upon the receipt of the registration or deregistration response message, the MIP client first searches for the credential of the mobile terminal according to the MT ID carried in the registration or deregistration response message, and calculates the MAC of the registration or deregistration response message according to the credential. Then, the MIP client matches the calculated MAC with the MAC carried in the registration or deregistration response message. If the calculated MAC is matched with the MAC carried in the registration or deregistration response message, the MIP client accepts the registration or deregistration response message. At the same time, the MIP registration or deregistration is finished.